In the repair work of a runway, a road or the like which is paved with concrete, there has been adopted an adhesion type overlay method, in which the surface of an existing concrete is overlaid with a new concrete. In the adhesion type overlay method, it is desirable that the new concrete is jointed to the existing concrete with sufficient jointing strength.
Thus, in order to improve adhesive properties of a construction-jointed portion, an existing concrete has hitherto been subjected to pretreatment for cutting the surface thereof before the overlay with a new concrete. The pretreatment is performed to remove an old surface layer and obtain an anchor effect, which is based on unevenness formed at the surface after the removal of the surface layer, on the new concrete.
The cutting method may be, for example, a method of using a vibration chipper to chip out the surface of a concrete.
However, the following technical problems remain in the cutting method in the prior art.
The pretreatment using a chipper involves many works depending on human hands. Therefore, the execution efficiency on a wide working spot is low. Moreover, workers are greatly effected by the generation of fine particles and vibration. Additionally, it takes long time to remove chipped concrete chips.
In order to improve adhesive properties of such a construction-jointed portion, for example, Japanese Patent Application Laid-Open No. 9-71902 discloses an overlay method of jetting highly-pressured water on a surface layer of an existing concrete for a pavement by water jet to form a macro-unevenness surface, jetting a large number of small and hard balls, in spherical or other forms, composed of a metal such as iron onto the macro-unevenness surface by shot blast to form numerous micro-unevenness having such an appropriate size that sufficient adhesion strength can be obtained, and overlaying the uneven surface which has the macro-unevenness and the micro-unevenness with a concrete material for a pavement, which has a given thickness, to form a surface layer on the uneven surface. According to this overlay method, the uneven surface can be easily and promptly formed without making pavement strength weak by the combination of water jet with shot blast. Therefore, the whole of the period of construction can be shortened, and further the adhesion strength of the paved surface for overlay can be improved still more than that in the case of using a chipper.
Even if the surface of an existing concrete is subjected to the surface treatment for forming unevenness by using both of water jet and shot blast, as disclosed in the above-mentioned publication, the adhesion strength of the newly formed concrete to the surface layer of the existing concrete varies according to the surface form generated based on the degree of the treatment.
Thus, in order to obtain sufficient adhesion strength, it is desirable to overlay, on trial, existing concretes having surface forms which are little by little different with a new concrete, measure the adhesion strength of the respective resultants by a tensile test or the like to specify an ideal surface form, and evaluate whether or not such an ideal surface form is formed on an actual pavement construction spot on the basis of the above-mentioned results.
However, in order to evaluate the surface-treated forms, it is necessary to measure the quantity of the unevenness at the surfaces of the existing concretes after the surface-treatment in their many points at the pavement construction spot, calculate characteristic quantities such as an average value of the unevenness quantities and a standard deviation thereof from the collected results, and compare the characteristic quantities with the characteristic quantities of the above-mentioned ideal surface-treated form. It takes a long time to carry out such measurement, collection of data, calculation and comparison on the spot and perform an exact evaluation. Thus, the shortening of the period of the construction may be hindered.
Thus, an object of the present invention is to provide a surface-treated form evaluating system making it possible to evaluate a surface-treated form of an existing concrete accurately for a short time in an adhesion type overlay method of surface-treating the existing concrete and then overlaying the treated concrete with a new concrete; and an ideal surface-treated form of an existing concrete making it possible to obtain sufficient adhesion strength of a new concrete to the surface of the existing concrete.